In general, surface-coated cutting tools include: inserts used by being detachably attached to a tip end portion of a tool bit in turning or planing of a work material such as various steels and cast irons; drills that used in drilling of the work material and miniature drills; and solid end mills used in face milling, groove machining, shoulder machining, or the like of the work material. Insert-type end mill tools with the insert detachably attached thereto that perform cutting in the same manner as in the solid end mills, are also known as coated tools.
In addition, in view of excellent wear resistance, coated tools including a complex nitride of Ti and Al (hereinafter, indicated by (Ti, Al)N) as a hard coating layer formed by coating using an arc ion plating (hereinafter, indicated by “AIP”) method, which is a type of physical vapor deposition, on a surface of a tool body made of tungsten carbide-based cemented carbide, are known.
For example, PTL 1 discloses that by depositing, on a surface of a tool body, a hard coating layer including a reformed (Ti, Al)N layer that includes a (Ti, Al)N layer satisfying a composition formula: (Ti1-XAlX)N (where X ranges from 0.40 to 0.60 in terms of atomic ratio) and that has such a crystal arrangement that in a case where the (Ti, Al)N layer is subjected to crystal orientation analysis by an electron backscatter diffraction apparatus, 50% or more in area is shared by crystal grains having a crystal orientation of <111> within the range from 0 to 15 degrees from the normal to the polished surface, and in a case where the angle formed between adjoining crystal grains is measured, the rate of the small-angle grain boundary (0<θ≤15°) is 50% or more, a coated tool in which the hard coating layer exhibits excellent fracturing resistance in high-speed heavy cutting can be obtained.
PTL 2 discloses a coated tool improved in adhesion and wear resistance of a hard coating layer in cutting of high-hardness steel having a Rockwell hardness of more than 50 (C-scale) by regulating the value of I(200)/I(111) to 2.0 or less when the diffraction intensity of (111) plane and the diffraction intensity of (200) plane are represented by I(111) and I(200), respectively, in X-ray diffraction of the hard coating layer in an end mill coated with (Ti, Al)N, complex carbonitride, and carbide of Ti and Al.
PTL 3 discloses that a coated tool has excellent cutting characteristics by virtue of a nitride hard coating film made to have 7.5YR to 10Y hue, 3 to 8 lightness, and 2 to 8 saturation by Mansell color charts by changing a nitrogen content in a film of compounds of Ti and/or Ti and Al and/or group 4A, 5A, and 6A metals.